An analog to digital converter (ADC) is a device that converts a continuous quantity to a discrete time digital representation. For example, an ADC may be an electronic device that converts an input analog voltage or current to a digital number proportional to the magnitude of the voltage or current. Typically, an ADC has a range of voltages that it can convert into unique digital codes. This range of voltages is called a conversion window. The ADC also has a resolution that defines the number of bits in each digital code.